Responsiveness of the Revised Low Vision Independence Measure (LVIM–R)

Abstract

Abstract Importance: The Low Vision Independence Measure (LVIM) was designed to measure the effectiveness of occupational therapy to improve visual ability in low vision rehabilitation. Objective: To validate the Revised LVIM (LVIM–R) as an outcome measure by determining its sensitivity to visual ability changes after occupational therapy. Design: In this observational study, LVIM–R scores were collected before and after customary low vision intervention. Setting: Home health agency or outpatient facility. Participants: Forty-four participants with a mean age of 80.2 yr (standard deviation = 11.2) and an average length of visual impairment of 6.2 yr. Twenty-three participants (52.3%) were treated in an outpatient setting, and 21 (47.7%) were treated in the home. The majority of participants were non-Hispanic White (92.8%) and had macular degeneration (54.5%). Intervention: Customary low vision intervention by occupational therapists. Outcomes and Measures: LVIM–R scores were collected before and after intervention, and participants’ pre- and posttest scores were anchored into Rasch-calibrated item parameters. Results: Paired t tests demonstrated significant increases in person measures with large effect sizes for both constructs of the LVIM–R, the visual field or scotoma (t[43] = 6.46, p < .0001; Cohen’s d = 0.92) and visual acuity (t[43] = 9.08, p < .0001; Cohen’s d = 1.14) constructs. Conclusions and Relevance: The LVIM–R is sensitive to changes in visual ability in clients who have good rehabilitation potential and can be used to examine the effectiveness of occupational therapy for low vision. What This Article Adds: The LVIM–R is useful for measuring occupational therapy outcomes in low vision rehabilitation in the home or in outpatient settings.